1. Technical Field
The invention relates to a system for the multipath reception of video signals, such as television signals, which may include image and/or sound signals.
2. Related Art
Multipath reception includes the reception of electromagnetic (“EM”) signals on one of several transmission paths or channels. Multipath reception of EM signals, including broadcast signals, may be accomplished using antenna diversity, and/or frequency diversity. Antenna diversity includes the use of one or more antennas. Frequency diversity includes reception on one of several receiver frequencies.
An antenna diversity receiver system is an EM receiving system that includes an EM receiver, which may be connected to one of several antennas. The antennas may be spatially separated. The EM receiver may include a telephone system, and/or a broadcast receiver, such as a television receiver or a telephone system. In addition, the EM receiver may include a selector switch that connects one of the antennas to the EM receiver on the basis of specified criteria, such as reception field strength and the interference, to receive the signal at an acceptable level of quality. This type of antenna diversity receiver system may be used in vehicles to receive broadcast signals, such as television signals. When used in vehicles, an antenna diversity receiver system may include window antennas integrated into the windows of the vehicle.
A frequency diversity receiver system is an EM receiving system that may include at least two radio receivers. One radio receiver may be an operating receiver, while the other radio receiver may be a search and test receiver that searches for alternative reception frequencies and tests the reception quality at those frequencies. If the search receiver finds an alternative reception frequency that provides a better reception quality than the current reception frequency, either the operating receiver is tuned to the alternate reception frequency or the search and operating receivers exchange roles. If the search and operating receivers exchange roles, the search receiver stays tuned to the alternate reception frequency and assumes the role of the operating receiver. The operating receiver assumes the role of the search receiver and thus searches for alternative reception frequencies and tests the reception quality at those frequencies. Frequency diversity receiver systems are suitable for use in vehicles because as the vehicle moves, the reception conditions may change as result of the changing surroundings.
Antenna and frequency diversity may be used in combination, for example, in a combined diversity reception system. A combined diversity reception system may include several antennas and receivers. The combined diversity reception system may also include a selector switch that may place the antennas in communication with the receivers in any combination.
Digital receiver systems, used for receiving digital broadcast signals, are becoming more widely used because an increasing number of radio and television programs are being broadcast digitally, for example using “Digital Video Broadcasting—Terrestrial” or “DVB-T.”